The Magazine for ENERGY EFFICIENCY and WATER CONSERVATION in Industrial Cooling Systems
Chiller System Optimization
Mar
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10 IN
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14 10 Glycol Tips for Water Chiller Operators
16 Central Plant Optimization for Pepco Energy Services’ Chiller Plant
24 5 Sizing Steps for Chillers in Plastic Process Cooling
26 Cooling Tower System Audit in Tough Mining Application
4 From the Editor
5 Chiller & Cooling System Industry News
10 Innovative MTA Free-Cooling Chiller Systems By Don Joyce, MTA-USA
14 Glycol Tips for Water Chiller Operators By Katlyn Terburg, Dimplex Thermal Solutions
16 Central Plant Optimization for Pepco Energy Services’ Chiller Plant By Tus Sasser, The Tustin Group
21 Tobacco Producer Protects Chillers with Self-Cleaning Filtration System By Marcus N. Allhands, PhD, P.E., Orival, Inc.
24 5 Sizing Steps for Chillers in Plastic Process Cooling By Bob Casto, Cold Shot Chillers®
26 Cooling Tower System Audit for a Tough Mining Compressed Air Application By Tim Dugan, Compression Engineering Corporation
31 Using 4 Waste Heat Sources for HVAC Optimization By Thomas Mort, CEM, Mission Point Energy
SUSTAINABLE MANUFACTURING FEATURES
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Over the years, we’ve interviewed many Energy Managers at multi-factory
corporations. After discussing energy management and compressed air best
practices, these subscribers have often asked if we could provide similar system
assessment and optimization case studies relating to their chiller and cooling
systems. Their machines have both compressed air and cooled water/fluid
connections! We hope to have answered their question positively with our new
Chiller & Cooling Best Practices Supplement.
MTA’s John Medeiros and Don Joyce have built a strong chiller business in the U.S. and
interestingly have trained many “air compressor people” to “turn off the blinders” and look
for chiller applications with their clients. Don has written an excellent article on the energy-
efficiency benefits of free-cooling and featured installations carried out by Bob Copell
of Scales Industrial Technologies.
Glycol prevents freeze-ups and protects heat exchangers from losing heat transfer efficiencies due
to the build-up of minerals or algae on their surface areas. Katlyn Terburg, from Dimplex Thermal
Solutions, provides us with advice in an article titled, “10 Glycol Tips for Water Chiller Operators.”
We have two excellent system assessment case studies on chiller system optimization. The first
is titled, “Central Plant Optimization for Pepco Energy Services’ Chiller Plant,” by Tus Sasser,
President of The Tustin Group. The second is titled, “Cooling Tower System Audit for a Tough
Mining Compressed Air Application,” by Tim Dugan, President of Compression Engineering Corp.
A case study on water filtration is provided by Marcus Allhands, from Orival, in his article,
“Tobacco Producer Protects Chillers with Self-Cleaning Filtration System.” Bob Casto, from Cold
Shot Chillers, provides handy chiller sizing information in his article, “5 Sizing Steps for Chillers
in Plastic Process Cooling.”
Last but not least, Thomas Mort from Mission Point Energy (Thomas is on our Editorial Board
and formerly Archer Daniels Energy Director and Association of Energy Engineers’ Energy
Manager of the Year) writes, “Using 4 Waste Heat Sources for HVAC Optimization.”
I’d like to welcome and thank many new readers from the chiller industry for investing their time
and knowledge with us. Our editorial mission is to help create high-ROI projects for factories,
based upon energy and water consumption savings, by increasing awareness. This can only happen
through the sharing of expertise from within the chiller industry. As we begin this journey, thank
you for investing your time and knowledge with Chiller & Cooling Best Practices – and please
look for our second Supplement coming in July!
ROD SMITH Editor tel: 412-980-9901 [email protected]
FROM THE EDITOR Chiller System Optimization
EDITORIAL ADVISORY BOARD
Indus
trial
Ener
gy M
anag
ers
Doug BarndtManager, Demand Side Energy-Sustainability
Ball Corporation
Eric Battino Productivity Senior Manager PepsiCo
Richard Feustel Senior Energy Advisor Leidos
Brad IkenberryEnergy Manager, North America
Michelin
William Jerald Energy Manager CalPortland
Jennifer MeierGlobal EH&S/ Plant Engineering Manager
Varroc Lighting Systems
Thomas Mort Chief Operating Officer
Mission Point Energy
Brad Reed Corporate Energy Team Leader Toyota
Brad Runda Global Director, Energy
Koch Industries
Don Sturtevant Corporate Energy Manager Simplot
2015 MEDIA PARTNERS
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MTA Introduces New LWT Series Low-Temperature Water Chillers
MTA-USA, LLC. has developed a special range of air-cooled chillers
designed for industrial applications to provide fluid temperatures down
to -4 ˚F. The entire LWT range is equipped with a high-efficiency, single-
pass counter-current flow, shell & tube evaporator and a new high-
efficiency, semi-hermetic piston compressor featuring the integrated
diagnostic technology module. In support of an environmentally friendly
refrigerant, the LWT range utilizes the more sustainable refrigerant
R-407F instead of R-404A.
The LWT Series features a new semi-hermetic piston compressor,
featuring the CoreSense™ integrated diagnostic module and unique
valve technology for higher energy efficiency. Piston compressor features
include standard suction and discharge valves, crankcase heater, oil
pressure sensor, muffler, vibration damper, and enclosure for adequate
acoustic insulation.
Comprehensive safety equipment includes phase monitor, HP pressure
switches, antifreeze sensors, and an active control system of the
compressor oil level. Further features include an electronic expansion
valve for refrigeration circuit control and a EC inverter controlled axial
fans with permanent magnets and integrated inverter speed control.
This water-chiller is designed for the following extended operating limits:
T water in max = 25 ˚F, T water out min = -4 ˚F with glycol, T ambient
max = +113 ˚F; T ambient min = -4 ˚F. In addition, the IP54 electrical
protection rating makes LWT chillers suitable for outdoor installation.
Visit www.mta-usa.com
CHILLER & COOLING SYSTEM INDUSTRY NEWS
“In support of an environmentally friendly refrigerant, the LWT range utilizes the more sustainable refrigerant R-407F instead of R-404A.”
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Mokon Earns ISO 9001:2008 Certification
Mokon, a leader in the design and manufacture of advanced heating
and cooling equipment for industrial markets, has been awarded ISO
9001:2008 certification for its Quality Management System. Mokon earned
this key accreditation by demonstrating its total commitment to providing
both the highest quality products and outstanding customer service.
“We are proud and excited about our ISO 9001:2008 certification,
which we feel is an essential tool when working with customers in global
markets,” Robert Kennery, general manager of Mokon, says. “We are
continually seeking ways to ensure our customers receive the highest
quality and safest products in the industry”.
According to the International Organization for Standardization
(ISO), the ISO 9001:2008 certificate is “based on a number of
quality management principles, including a strong customer focus,
the motivation and implication of top management, the process
approach and continual improvement.” Over one million companies
and organizations in over 170 countries have earned ISO 9001:2008
certification.
Mokon received its Certificate of Registration from NSF International
Strategic Registrations, an accredited registrar that performs assessments
of management systems against the requirements of national and
international standards for quality. The scope of Mokon’s registration
is associated to all aspects of its processes relating to the design,
development, manufacturing and service of standard and custom systems.
For 60 years, Mokon has designed and manufactured its circulating
liquid heating and chilling equipment in the United States. Mokon
consistently demonstrates its ability to foresee the evolving needs of
customers in industries such as plastics, die casting, food processing,
pharmaceutical, composites, chemical processing, rubber, converting
and more. One of Mokon’s primary goals is to continually improve the
design, quality, delivery and durability of its products and reach a high
level of customer satisfaction.
Visit www.mokon.com
Chillers at FABTECH 2014
The depth and breadth of manufacturing’s reach into the U.S. and global
economies was on display at the recent FABTECH 2014 exposition and
conference in Atlanta. FABTECH, held November 11-13, 2014 at the
Georgia World Congress Center, is the largest annual metal forming,
fabricating, welding and finishing event in North America. Visit www.
fabtechexpo.com for information on the November 2015 event in Chicago.
More than 30,800 attendees from over 70 countries attended FABTECH
2014. During the three-day expo, attendees visited 1,477 exhibitors
to see live equipment demonstrations and find cost-saving solutions.
The exhibits covered more than 550,000 net square feet.
The chiller industry is very well represented at the show. Chillers play
a critical role in the robotic resistance welding and the metal-cutting
processes of the metal fabrication industry.
Haisar Shehadeh and Whitney Mayo at the Semyx booth. The hydraulic systems on their water jet cutting machines are cooled by chillers.
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I enjoyed meeting Haisar Shehadeh and Whitney Mayo from Semyx.
Semyx is a global company specializing in water jet cutting machines.
Based in Dalton, Georgia, Semyx water jet machines provide
precise cutting of steel and other metals. A system component is the
“Intensifier” which increases water pressures to between 60,000 and
90,000 psi. Stay out of the way! Semyx uses chillers to cool the hydraulic
systems (www.semyx.com).
T.J. Snow is a manufacturer of resistance welding equipment and
accessories. Based in Chattanooga, they pride themselves on training
and offer their clients and employees significant training resources.
Their welding system knowledge has also led them to help their clients
better manage their utilities — so they also offer compressed air dryers
and chillers. This is a great example of why our publication is expanding
to cover chillers.
Chillers provide temperature control to the spot welding process. If
things get too cool, weld quality can be impacted. Too hot and the life
of the electrode tips is impacted. Meanwhile, pneumatic air cylinders
provide force for the rocker arm. The T.J. Snow Company often places
air storage and refrigerated air dryers to ensure reliable performance.
Aside from the fact he’s a pilot (as are half his management team)
who flies himself to business meetings, Thomas J. Snow is one of
those business founders who has forgotten more than I’ll ever know
about his expertise (welding) — yet he never makes one feel that
way. The success of their premium welding equipment systems have
the company on an amazing growth path and they are a heck of a feel-
good “Made in the U.S.A.” story (www.tjsnow.com).
The Parker FAF Division had a booth where they displayed the
Hyperchill Series chiller able to support the innovations the Parker
Automation people provide the resistance welding market. The RIP
Robot Install Partner designed for resistance welding machines
features a WRA water return actuator and a double-air cylinder that
creates a vacuum to pull water off a piece. The WBB water block
reduces water consumption and the air preparation units ensure air
quality (www.parker.com/faf).
Cold Shot Chillers had a nice booth featuring their chiller line ranging
from ½ to 150 ton chillers. Mark Johnson and Bob Casto spoke
knowledgeably about their target markets in plastic processing,
metalworking high temperature applications, bakeries, and other
food and beverage applications. Please take a look at their interesting
article in this issue on chiller sizing for plastic processing applications
(www.waterchillers.com).
Johnson Thermal Solutions caught my eye as Sales Director Denise
Klaren explained their focus is on mission-critical design of custom
chillers. Based in Coldwell, Idaho, they were founded ten years ago by a
group of chiller industry veterans. They provide chillers for medical MRI
and CT Scanner equipment, to the dairy industry, and for critical HVAC
applications such as data centers. They’ve built chillers ranging from
three to thousands of tons of cooling capacity. At the show they were
Thomas J. Snow and Mark Pepping (left to right) at the T.J. Snow booth with their new Rocker-Arm spot welding machine rated to consume five gallons per minute of chilled water.
MTA exhibited their chiller technologies. Pictured left to right are MTA executives; Angelo Mastrangelo, John Medeiros, Bob Copell (Scales Industrial Technologies), Don Joyce, Lewis Rains, and Andy Poplin (Atlas Machine & Supply).
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CHILLER & COOLING SYSTEM INDUSTRY NEWS
showcasing their new 3 to 30 ton ET Series engineered for high flow
pumps used in welding (www.johnsonthermal.com).
MTA is on quite a roll with their chiller business. John Medeiros and
Don Joyce are finding success supplying their TAE Series chillers to
welding applications and with air compressor distributors learning to
apply chillers. As Bob Copell from Scales Industrial Technologies said,
“We used to have blinders on and went straight to the compressed air
system. Now, we are also assisting our clients with their cooling, blower
and vacuum systems.” Andy Poplin from Atlas Machine was also working
the MTA booth and learning about the welding and metal fabrication
applications. Please take a look at Don Joyce’s article on free-cooling
in this issue (www.mta-usa.com).
SMC was also present with their HRS Series thermo chillers kept in
inventory at their headquarters in Indianapolis. According to Product
Manager Scott Maurer, chillers are one of many products they offer
clients to support arc welding processes. Other products include spatter-
resistant pneumatic cylinders, flow meters for air and gas, and digital
flow meters to control water flow at the weld tips (www.smcusa.com).
Frigel Displays Innovative 3PR Controller for Process Cooling at NPE 2015
Visitors to the Frigel booth W7991 at NPE 2015 will get a close look at
the world’s most efficient and sustainable plastics process cooling system
— now more adaptable to meet plastics processors’ specific needs.
Among the latest Frigel innovations on display will be the new 3PR
Intelligent Control System, which provides processors with even easier
and more precise control over their Frigel cooling systems. Featuring
a unique 7", full-color touch screen interface, 3PR allows processors
to achieve better closed-loop process cooling system accuracy with
more data points at their fingertips.
As a next-generation controller, 3PR automatically adjusts the integrated
Frigel cooling system to ensure optimum performance based on a
wide range of system operating parameters. The controller provides
users with extended functionality for monitoring and adjusting system
Parker displayed the Hyperchill chiller along with their Robot Install Partner program for resistance welding equipment. Pictured (left to right) are: Phil Kubik, Dale Zimmerman, John Schuster, Tim Ritter and Allan Hoerner.
Denise Klaren from Johnson Thermal Solutions with their new ET Series chiller.
Mark Johnson and Bob Casto from Cold Shot Coolers.
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parameters using real-time data to further enhance system performance.
Troubleshooting features, combined with remote access capability,
help operators quickly resolve issues and minimize downtime associated
with routine maintenance. The controllers’ onboard memory further
aids in troubleshooting and uptime by continuously storing key
operating conditions, which can be downloaded for detailed analyses.
“The new 3PR Intelligent Control System allows processors to gain more
control of the process cooling system with an intuitive HMI that relays
information in the language specific to the user, versus software codes,”
said Al Fosco, Global Marketing Manager at Frigel. “The controller
is also easy to use and it allows for more efficient tracking of real time
data to ensure optimal system performance.
Visitors to the booth will be able to experience 3PR’s intuitive controls
first hand via an interactive touch-screen app.
Other Frigel innovations on exhibit include:
pp Ecodry 3DK Closed Loop Adiabatic Liquid Cooler: The next generation of Frigel’s patented adiabatic system is easily adaptable to any climate, system or process. The system gives processors the ability to increase water and energy savings, improve cooling precision, reduce maintenance and save space.
pp Microgel Chiller/TCUs: Frigel’s compact, portable units are available as single- or dual-zone models with water- or air-cooled options, which allow users to maintain precise, microprocessor-controlled temperature at molding machines. When compared to central chillers, Frigel Microgel units save 60 percent of energy costs and also conserve space.
Frigel’s exhibit will also showcase the VFD Pump Set, HB-Therm
Temperature Control Unit and the Turbogel Temperature Control Unit.
Digital presentations will be available on all of these products, also
including Frigel’s complete line of central chilling systems.
For more information on what to expect from Frigel at NPE, visit
www.frigel.com/npe.
About Frigel
Based in Florence, Italy, Frigel Firenze SpA designs, manufactures
and services advanced process cooling equipment for customers
worldwide. Foremost among Frigel’s products is the Ecodry system,
a unique, closed-loop intelligent cooling system, which is proven to
dramatically reduce water and energy use and maximize production
in thousands of installations. Frigel also provides high-efficiency
central chiller units as well as a full range of precise machine-
side temperature-control units to meet specific needs of diverse
applications. Visit www.frigel.com for more information.
Shown is a selection of data screens available on the new 3PR Intelligent Process Control System from Frigel. The intuitive display provides processors with even easier and more precise control over their Frigel cooling systems.
“Chillers play a critical role in the robotic resistance welding and the metal-cutting processes of the metal fabrication industry.”
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cpProcess cooling system applications
experiencing constant production loads
generating high process fluid temperatures are
particularly good candidates to take advantage
of low ambient temperatures. Low ambient
temperatures can be used as a “free” energy
source, replacing the electricity required to
run refrigeration compressors, in what is
known as a free-cooling chiller system.
Free-cooling systems are not new although
differences in design efficiencies exist. Partial-
mode, free-cooling, which is fully automated
and integrated into the chiller system is an
innovation.
Traditional free-cooling systems are “all or
nothing” systems where the process fluid is
either cooled by low temperature ambient
air or by the refrigeration compressors. An
innovation in free-cooling has been developed
with the introduction of partial-mode free-
cooling, allowing for a significantly broader
range of application temperatures and
significantly increased energy savings.
Total Free-Cooling Only
A total free-cooling system, normally used
only during very cold winter months, takes
advantage of low ambient temperatures to cool
the fluid (water) in the circuit in what’s known
as a dry cooling system (ambient air to water
heat exchanger). The evaporator (refrigeration
to water heat exchanger) is bypassed and the
refrigeration compressors in the chiller are
OFF and energy is saved.
The process cooling system will automatically
switch to the total free-cooling mode, when
ambient temperatures are in a range up to
18 ˚F lower than the required fluid outlet
temperature. Under these conditions, all the
refrigeration compressors, in the condensing
section of the chiller, will be switched OFF.
Under even lower ambient temperatures, the
Innovative MTA Free-Cooling Chiller SystemsBy Don Joyce, MTA-USA Inc.
The MTA Aries Free-cooling Chiller Systems
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electronic controller reduces step-by-step the
rotation speed of the fans of the free-cooling
section, all the way to shutting the fans down
under extremely low temperatures.
In case the ambient temperature falls to
extremely low levels, the 3-way valve modulates
and will by-pass part of the flow by mixing
it with the outlet fluid from the coil, always
maintaining the perfect control of the fluid
outlet temperature.
Traditional free-cooling process cooling
systems will stack heat exchangers (the
evaporator and the ambient air-to-water heat
exchanger) with both connected to one set
of oversized fans able to provide free-cooling
and support the condenser.
Partial and Total Free-Cooling Modulation
MTA Process Solutions, has introduced partial-
mode free-cooling. This allows free-cooling to
offer it’s energy-saving benefits to applications
experiencing the ambient temperatures often
seen during the transitional seasons of Fall
and Spring. Integrated into one chiller system,
the system automatically decides, based upon Ratio of usage of the free-cooling system during one year (data referred to shift of total 24h/day at temperature of the fluid in/out = 59/68 ˚C)
Fig.1 Free-cooling solution of MTA with the independent air-to-water heat exchanger and smaller, separate fans.
Fig.2 Traditional free-cooling solution with stacked heat exchanger coils using one over-sized fan.
“Low ambient temperatures can be used as a “free” energy source, replacing the electricity required to run refrigeration
compressors, in what is known as a free-cooling chiller system.”— Don Joyce, MTA-USA Inc.
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ambient temperatures, whether to operate as
a chiller or as a partial or total free-cooler.
When working in free-cooling mode, these
chillers use a modular operating logic and
the free-cooling of the water can be done
in all seasons of the year, either with the
refrigeration compressors “ON” (Partial Free-
Cooling) or with the compressors “OFF” (Total
Free-Cooling).
Partial-mode free-cooling is made possible by
separating the chiller and free-cooling systems
— each heat exchanger sets using their own
fans. In the partial free-cooling mode, the
system starts to “free” cool when the ambient
temperature is 3.6 ˚F below the fluid inlet
temperature. Water is routed via a three-way
valve first to the free-cooler and then it goes
to the chiller. The controller automatically
reduces the work of the compressors by
throttling the cooling capacity by controlling
the 3-way valve (which controls where the inlet
water goes). During the transitional months
of Fall and Spring, free-cooling acts as a pre-
cooler and significantly reduces the work (and
energy consumption) of the chiller.
Case Studies from the Northeast U.S.A.
Scales Industrial Technologies helps industrial
and medical clients maintain the reliability
and quality of chiller, blower, vacuum and
compressed air systems — while always
keeping an eye out for how to reduce a client’s
operating expenses.
“If our customers don’t succeed in their
businesses, neither will we,” says Bob
Copell, Process Cooling Specialist covering
several New England states. “It’s rewarding
to help customers take a longer-term view
on reducing operational costs associated with
maintenance and decreased energy and water
consumption.”
A growing plastic injection molding plant
needed 65 ˚F water to cool their plastic molds.
The existing chiller system wasn’t going to be
able to handle the growing demand for chilled
water, and the plant was receiving proposals
for new chillers.
“While the maintenance manager and I were
discussing the air compressor system design
for the new facility, we were leaning on the
existing chillers inside. I just happened to
notice that the chiller fluid temperature was 65
˚F and it was only 20 ˚F outside and snowing,”
Copell explained, “I asked if they would
consider a proposal for a high efficiency,
cycling free cooling chiller. I explained that
this type of packaged chiller would utilize the
outside air to cool their process for at least five
months out of the year which would save them
considerable operating costs.”
To make a long story short, the client installed
an MTA free-cooling system using both partial
and total free-cooling modes. The local utility
helped finance the purchase, and the simple
ROI was achieved within 14 months.
The success and growth of a company will
place strains upon the utilities required by
the facility to support production equipment.
A manufacturer of point-of-use commercial
and residential water heaters required
cool water to test their heaters. The existing
testing method used four five hundred gallon
tanks supplying approx. 70 ˚F water to the
heaters being tested. The water would return
to the tanks at 140 ˚F. They would then add
city water to temper it and try to bring the
temperature down.
“The factory was consuming significant
amounts of city water while delivering
inconsistent water temperatures to the test
lab,” according to Mr. Copell, “We installed
a MTA free-cooling system with one glycol
loop and we’re running on free-cooling 6-7
months a year.” The project qualified for
incentives from the local utility. The plant has
also reduced their water consumption, the
cost of their sewer bill — all while improving
the quality and reliability of their test process
by now delivering a consistent 65 ˚F water
temperature to the lab.
A Case Study from the U.K.
A large company wanted to replace the
existing chiller systems on two three-story
office buildings at their main campus. They
run a 24-hour, seven day a week operation and
needed an air conditioning system to match.
The old system was out of date, oversized
and did not have the capacity to handle the
requirements of modern air conditioning.
The MTA chillers offered the client reduced
noise levels, due to the availability of three
differing acoustic versions. There are high EER
levels, especially at part loads (ESEER). They
are ideal for large hydronic air conditioning
installations in public and private surroundings
and allow start up and operation even in the
most severe conditions.
INNOVATIVE MTA FREE-COOLING CHILLER SYSTEMS
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The engineering contractor was looking for
an ambient temperature in each room of 68-
69 ˚F. The customer wanted the most energy
efficient, cost effective and easy to install
solution — so they decided to replace the
existing roof-top chillers with MTA chillers
featuring 9 and 12 compressors each,
delivering chilled water for air conditioning.
Importantly, the MTA chillers featured
integrated free-cooling.
The MTA distributor realized free-cooling
would make a significant difference in cutting
energy bills for the client. The chillers were
designed with a water temperature of 54 ˚F.
Here the system cut-in with free-cooling at two
degrees below this level. When this happens no
refrigerant is required and energy use begins
to tumble. The MTA distributor estimated this
could lead to energy savings during the winter
months of as much as 70 percent. During the
warm summer months, the system can offer
savings of up to 40 percent.
The first system was installed over the Easter
weekend by the MTA Distributor. Two McQuay
1Mw chillers were replaced by:
pp 2 pieces GALAXY Tech 270 N with S&T evaporator and electronic fan speed control
pp 2 pieces AFV 300 N with electronic fan speed control. Emerson Crane Hire of Dagenham assisted with the rooftop work.
Four weeks later two McQuay 1Mw chillers
were removed from the second building and
replaced by Polar Cooling Services Ltd with:
pp 2 pieces GALAXY Tech 285 N with S&T evaporator and electronic fan speed control
pp 2 pieces AFV 300 N with electronic fan speed control
The new chillers were installed, fixed to the
water and electrical circuits, and commissioned
ready for the
start of the working week. The new chillers run
on R410a, replacing the outdated R22. Each
MTA system offers remote monitoring.
The free-cooling showed its’ worth
immediately. During the first week the
building was cooled by the free-cooling
system only, as the temperature outside was
very cold — saving seventy percent in energy
costs. Since then whenever the ambient
temperature has reached 68 ˚F there have
been energy savings of at least forty percent
over the prior system.
Summary
The use of free-cooling technology allows
users to reach a reliable pay-back time
on the investment compared to traditional
water chillers. Depending on the weather
conditions and on the fluid temperatures,
the return on investment is almost always
close to one year. An innovation in free-
cooling has been developed with the
introduction of partial-mode free-cooling,
allowing for a significantly broader range of
application temperatures and significantly
increased energy savings.
For more information contact Don Joyce, National Sales Manager, cell: 980-241-3970 email: [email protected], of John Medeiros, Managing Director, tel: 716-693-8651, email: [email protected], MTA USA Inc., www.mta-usa.com.
For more information also contact Robert Copell, Process Cooling Specialist, Scales Industrial Technologies, tel: 800-627-9578 x 3117, email:
[email protected], www.scalesair.com
A MTA Free-cooling Chiller System
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cpThe use of an industrial inhibited glycol and water mixture is
recommended in most water chiller systems. Ethylene and Propylene
are the two standard types of inhibited glycols commonly used.
The main job of glycol is to prevent freezing of the process fluid
and ensure consistent flow at the operating temperature. Inhibited
glycols will also prevent formation of scale and corrosion while
protecting metals such as brass, copper, steel, cast iron and aluminum.
Water systems treated with an inhibited glycol will also be protected
from algae and bacteria that can grow and degrade the fluid system
performance. This brief provides ten basic tips for glycol users in
water chilling operations.
1 Don’t Mix Glycols
Do NOT mix different types or brand names of glycol. This
can result in some inhibitors precipitating out of the solution.
Mixing glycols will also gel and clog filters and prevent proper
flow rates. If switching glycol types, it will be necessary to run
a thorough flush and clean of the fluid system. Once that’s
done, it’s okay to change over.
2 Don’t Use Automotive Grade Anti-Freeze
Do not use automotive grade anti-freeze in the chiller
process. These types of glycols are not designed for industrial
applications and may cause problems with heat transfer or
fluid flow. Many automotive glycols contain silicate-based
inhibitors that can coat heat exchangers, attack pump seals,
or form a flow restricting gel.
3 Check Local Environmental Regulations
Check state and local codes when selecting the process fluid.
Certain areas may have environmental regulations concerning
the use and disposal of glycol or other additives.
4 Ethylene Glycol for Most Standard Industrial Applications
Ethylene glycol is the standard heat-transfer fluid for most
industrial applications. This type of glycol can be used in
any application where a low-toxicity content is not required.
10 GLYCOL TIPSfor Water Chiller OperatorsBy Katlyn Terburg, Dimplex Thermal Solutions
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SUSTAINABLE MANUFACTURING FEATURES
Ethylene glycol has moderately acute oral toxicity and should
not be used in processes where the fluid could come in
contact with potable water, food, or beverage products.
5 Propylene Glycol for User-Contact Applications
Propylene glycol maintains generally the same freeze
protection and corrosion/algae prevention levels as ethylene
glycol – but has a lower level of toxicity. This type of glycol
is more readily disposable than ethylene and safer to handle.
Propylene glycol is commonly used in the food industry and
in applications where the user may come in frequent contact
with the fluid.
6 Difference Between Ethylene and Propylene Glycol
At very cold temperatures, propylene glycol become more
viscous, changing the heat exchange rate slightly. Some chillers
are designed for that compensation so that either glycol type
can be used. Ethylene is more widely known due to its lower
purchase price, making it more economically feasible for
factories with significant purchasing volumes.
Koolant Koolers recommends propylene as its MSDS (Material
Safety Data Sheet) handling is less rigorous, making it easier
for facility maintenance staff if they ever need to fill or clean
up a glycol spill. Please note that some U.S. states prohibit the
use of ethylene glycol for environmental reasons.
7 Use Distilled or Reverse-Osmosis Water
Thought and planning should be dedicated to selecting the
water to mix with glycol. Water should come from a good
quality, filtered source meeting the requirements of the
process machine manufacturer. Koolant Koolers recommends
the use of distilled or reverse-osmosis water for the glycol/
water mixture.
8 Beware De-ionized and City Water
De-ionized water can be used to fill the chiller process initially,
but should not be maintained at a de-ionized state thereafter.
Unless the chiller has been ordered and designed for use
with water that is continually de-ionized, the fluid will actually
attack certain metals within the chiller and cause damage to
some components. Check with the chiller factory before using
de-ionized water to check for compatibility.
Neither is the use of regular tap water recommended.
Water from “the city” or “the ground” contains deposits
and additives which can decrease component life and
increase maintenance requirements.
9 Applications Drive Water/Glycol Mix Percentages
The location of the chiller and environmental concerns must
be taken into account when selecting the proper mixture of
glycol and water for the chiller process. A process located
completely indoors, with no chance of freezing, will require
less glycol than a system located outdoors where low
temperatures can cause the fluid to freeze and piping to burst.
Applications with a very low operating temperature (below
20 ˚F) should use a glycol mixture equivalent to an outdoor
system. After selecting the proper glycol and water types, use
the following chart to determine the recommended mixture
depending on the application and location of the process. The
glycol percentage figures in the chart below will apply to any
brand of ethylene or propylene glycol.
Application Glycol % Water % Freeze Point
Indoor Chiller
and Process
30 70 5 ˚F / -15 ˚C
Outdoor
Chiller/Low
Temperature
50 50 -35 ˚F / -37 ˚C
*Figures based on the performance of Koolant Koolers K-Kool-E brand of ethylene glycol.
10 Fluid Maintenance and Filtration
Maintaining clean process water and the proper glycol
content will extend the life of the system and reduce costly
down-time. If the chiller was not equipped with a fluid filter
from the factory, it is highly recommended to install some sort
of filtering system to remove unwanted dirt and debris.
For more information contact: Katlyn Terburg (Parts Sales) [email protected] Mike Omstead (Director of Service) [email protected] Tel: 269-349-6800, www.koolantkoolers.com
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cpPepco Energy Services’ (PES) Midtown Thermal Control Center
(MTCC) in Atlantic City, New Jersey, sells chilled water and steam to
multiple Atlantic City casinos, Boardwalk Hall and Pier Shops. PES is
also responsible for stand-alone remote heating and cooling plants for
the Atlantic City’s major casino’s as well as the Atlantic City Convention
Center including its 2.4 Mw solar array.
Patrick Towbin, VP of Asset Management for PES, was brought on
board to improve the performance of the MTCC plant. It didn’t take
long for him to see that the 16,200 Ton chiller equipment accounted
for a large portion of the MTCC’s production costs, and that there
were opportunities to improve the efficiency of the operation of this
equipment. He hired John Rauch to head the plant’s operational
management team. The new mandate, under the direction of Towbin
and Rauch, was to seek cost effective ways to improve the operations
of the MTCC, especially the larger contributors to production costs.
Holistic Approach Needed
Within a short time of his arrival, Rauch, as the new PES Plant
Operations Manager, saw that MTCC was relying on the same
equipment and processes that were put in place when the plant was
Pepco Energy Service Midtown Chiller Plant. The chiller plant operates 24 hours per day, 365 days per year, providing essential chilled water via a 42” header to numerous Atlantic City
casinos, Pier Shoppes and the Atlantic City Boardwalk Hall and Visitors Center. The 16,200 Ton plant has 4-York 4160v series counter flow chillers and 10-York 480v VSD series counter flow
chillers. System pumping capacity is 40,000 GPM. A total of 14 chillers are in the plant—16,200T
CENTRAL PLANT OPTIMIZATION YIELDS UP TO 25% EFFICIENCY IMPROVEMENT FOR
PEPCO ENERGY SERVICES’ CHILLER PLANTBy Tus Sasser, The Tustin Group
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SUSTAINABLE MANUFACTURING FEATURES
built over 15 years ago. “We started our review by asking ourselves
how can we produce chilled water more efficiently so that we can
improve our bottom line. With this as our guide, we identified
many opportunities for improving efficiency at the plant. Not only
in the chilled water production process, but also in measuring and
monitoring the output of the production process.”
Rauch’s investigation showed that the plant was being operated and
maintained with a series of independent components and controls,
many of which had been modified over the years. From experience,
Rauch knew that even the most efficient components fail to meet
their promised efficiency over time. He believed it was essential
to look beyond component-based efficiency and employ a holistic
approach where components work optimally as part of a networked
interrelated system.
Rauch lost no time in contacting Brad Pappal, General Manager of
Tustin Energy Solutions (TES), a commercial energy management
company headquartered in Norristown, Pennsylvania, to help evaluate
the situation and submit a proposal for improvements. Rauch had
worked with Pappal’s team in the past on projects that successfully
and significantly reduced energy consumption. What neither party
knew at the time was the amount of effort it would take to compile
the data necessary to develop a baseline and prepare a proposal
for improvements. Once the initial survey and site assessment was
complete, it was clear that the largest opportunity for cost effective
energy reduction was in the chilled water production process. However,
the opportunity was not simply replacing or adding equipment. It
was modifying the controls strategies with which chilled water was
produced. TES then reached out to Kiltech, Inc., their partner for
central plant optimization, to review the opportunity.
Developing a Baseline
“Without good data and a good control system, how do you know
if, or what, you need to optimize?” explained Rauch. “For over 10
months in 2012 we worked with TES and Kiltech, Inc. on the data
collection/validation phase in order to understand what we had so that
we could very accurately portray what we could gain by implementing
a central plant optimization system. We reviewed all prior electric
bills and upgraded many flow and temperature transmitters to
make sure we got accurate baseline data.” Rauch understood that
improvements in the chilled water production process would be
evaluated in competition with other capital expenditure options under
consideration by management. Because capital budgets are limited,
it was vital that he accurately quantify the benefits to be achieved with
the expenditure to gain approval to proceed.
Once the development and costing process was complete, Towbin spent
countless hours reviewing the financial implications of the project.
However, before he would submit the proposal to the corporate decision
makers in Virginia, he asked to see a working site and to speak to the
end users. Kiltech, Inc. scheduled several site visits for Towbin to review,
assess, and interview which provided the confidence he needed to move
the proposal forward.
The proposal showed that PES could reduce its chilled water production
costs by well over 20% by implementing the proposed chiller
optimization changes and other energy efficiency measures. “Over twenty
percent is a big number and management was initially skeptical,” said
Rauch. “It took almost four months of additional validation to address
their questions and to demonstrate that the calculations were accurate.”
For Towbin, who had been involved with similar projects before, the
fast payback was obvious. Towbin relied upon his expertise in analysis,
engineering, and asset management to convince his management of the
excellent economics associated with the project. The project qualified
for a half-million dollar rebate from the New Jersey Office of Clean
Energy’s NJ SmartStart Buildings® Program, and also resulted in nearly
25% improvement in operating efficiencies. In the end, and after
thorough due diligence on their part, Towbin and Rauch prevailed
and the project was approved.
Optimization Measures
The proposal called for TES to make numerous energy efficiency
upgrades including VFDs, and to utilize a non-proprietary automated
plant optimization application from Kiltech, Inc. called CPECS (Central
Plant Energy Control System). “When CPECS is deployed (either in
new construction or retrofit) it routinely achieves annual averages
of 0.55 kW/ton and lower for the entire chiller plant, (depending
on the application), thus translating to significant annual energy
and cost savings,” explained Pappal. TES application engineers
and programmers worked closely with Kiltech, Inc. to customize the
system’s software that automatically sequences the operation of the
entire chilled water plant. The CPECS networked optimization software
was designed to take advantage of the Plant Control System (PCS) to
maximize central plant efficiency. “We were able to interact with the
plant’s existing Allen Bradley Rockwell Plant Control System to fully
optimize the mechanical systems in the plant,” added Pappal.
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SUSTAINABLE MANUFACTURING FEATURES
The CPECS’ networked onsite server that is deployed on the backbone
of the current PCS, receives data, processes and models the data and
provides historical, real-time, and predicted data. The data outputs
from the CPECS provide the operational strategies that are automatically
implemented by the plant control system. Based upon the energy
efficiency measures developed during the initial verification process,
TES upgraded various motor starters and system critical instruments
required for optimization.
All About the Algorithms
“The CPECS platform uses a non-proprietary, open protocol and
fully modeled methodology. The approach is model and simulation
driven and is customized to PES’ plant and operations. At the heart
of the software is an algorithm that is computing all possible chiller,
pump and cooling tower sequencing permutations, modified flows,
set points and load limits. These calculations find the combination of
equipment and speeds that result in the lowest kW input and/or the
lowest instantaneous cost of production,” explained Joshua Kahan,
General Manager for Kiltech, Inc. “All of this is recorded, reported
and implemented in real time.”
“It’s all about the algorithms,” explained Rauch. “The system has
what’s called a Brute Force Optimizer algorithm that constantly
calculates the most efficient operation scenario. Algorithms run
every 15 minutes, 24/7. They make real- time automatic adjustments
to the system based on real-time building loads. The optimization
software then simulates that data and directs the PCS for adjustments
needed to maximize the system performance. The software has
complete knowledge of compressor, tower and pump performance
characteristics, which it uses in real time to modulate control levels
to all VFDs, pumps and machines.”
“If you have the right algorithm and you work with the details that go
through it, then it’s pretty straightforward,” explained Towbin. “The
program’s successful implementation is largely due to how much
patience Rauch and the operators had to make sure the algorithm
was programmed correctly.”
The program’s continuous feedback loops provide detailed, real-time
and historical performance data so operators can quickly detect,
diagnose and resolve system faults. “They can see the data via
easy-to-read graphs and charts that allow for quick diagnosis of
faults,” said Rauch. “If a chiller goes down for maintenance, the
software recalculates, and readjusts, and reassigns the process
workload accordingly.”
Concern Over Job Security
Plant operators were initially skeptical about a “Hands Off” system
taking over completely. “The idea of a plant running relatively ‘hands
free’ in terms of operating efficiency led to a concern about job
security,” explained Rauch. “However, the way things have worked out,
operators are now more available to do maintenance, shutdowns, and
system analysis, and can do so without missing critical control changes.
The system’s automated demand response, used for balancing supply
and demand, allows operators to program the optimization system so
it stays under a predetermined plant electrical load. “The optimized
control program will now do the adjustments for them,” said Rauch.
“This is a long way from the days when operators had to stare at a
CENTRAL PLANT OPTIMIZATION YIELDS UP TO 25% EFFICIENCY IMPROVEMENT FOR PEPCO ENERGY SERVICES’ CHILLER PLANT
“The chiller plant optimization enabled PES to obtain a $500,000 rebate through the New Jersey SmartStart
Buildings® program — the maximum allowable rebate.”— Tus Sasser, The Tustin Group
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SUSTAINABLE MANUFACTURING FEATURES
screen and stress over all the things that had to be tweaked, or turned
on or off, to meet a demand response number at peak hours. Many of
the MTCC’s customers are event driven and when there are large events,
usage can increase dramatically. The CPECS can now help PES better
manage these peak usage episodes.”
Side Benefit
“In addition to achieving operational efficiencies and savings, this
central plant optimization project clearly demonstrated how automated
optimization of a complex plant like MTCC can help the owners meet
their operational goals by helping them achieve production reliability,
as well as enhanced visibility into operations and equipment that enables
them to foresee challenges that may impact performance or operations,”
said Kiltech’s Joshua Kahan.
One of the things about the CPECS that impressed Towbin was actually
finding new opportunities for additional efficiencies. “You start to see
things that you never knew were acting as a drag on our production
efficiency,” he said. “The side benefit is that it helps you optimize your
plant and your operations because the system brings to light situations
that you had never questioned before. In the end, it was a very deductive
way to implement improvements in our plant.”
Annual Savings, Energy Rebate and Additional Benefits
The chiller plant optimization was completed in 2013. Since
deployment, it has become commonplace to see daily savings of
30% relative to baseline. Going forward, savings are expected to be
20-25% annually. “The Midtown plant operates at near maximum
cooling capacity during the summer months and there are limits to the
optimization based on weather conditions and customer occupancy,”
explained Pappal. “PES benefits most during shoulder and winter
months. The demand is much lower and the maximum benefits
of optimization are realized. Regardless, the first priority of cooling
is always met.“ In addition, Towbin added that “now we have people
from all over the company coming here to see the efficiencies we
have gained.”
The chiller plant optimization enabled PES to obtain a $500,000 rebate
through the New Jersey SmartStart Buildings® program — the maximum
allowable rebate. The NJ program makes financial incentives available
for projects that provide significant long-term energy savings.
During the chiller plant optimization, TES repurposed two additional
aging proprietary control systems at MTCC and remote mechanical
plant for the Atlantic City Convention Center. Along with upgrades and
equipment, TES/ Kiltech combined services will save PES over $500,000
annually in energy, repair, and unnecessary services.
“Plant optimization where components work optimally as part of a
networked, interrelated system has allowed us to reach a new level of
plant efficiency,” said Rauch. “With the right team, you can make the
technology work seamlessly. And that is what we have here, optimization
24/7, helping us save upwards of 25% annually.”
For more information contact Tus Sasser, President, The Tustin Group., email: [email protected], tel: 610-539-8200. The Tustin Group is a provider of advanced HVACR mechanical services, building energy management solutions, water management services, fire protection systems and retrofit construction services for commercial, industrial and institutional customers. Visit www.thetustingroup.com.
For more information about Pepco Energy Services visit www.pepcoenergy.com.
For more information about Kiltech, Inc. visit www.kiltechcontrols.com.
Baseline Performance Data: October 1, 2013 – July 31, 2014 (Total electric savings for the period 5,370,000 kwh)
CENTRAL PLANT OPTIMIZATION YIELDS UP TO 25% EFFICIENCY IMPROVEMENT FOR PEPCO ENERGY SERVICES’ CHILLER PLANT
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SUSTAINABLE MANUFACTURING FEATURES
TWO SPECIAL SUPPLEMENTS FOR 2015!In order to bring special attention to blower and vacuum system optimization
opportunities and industrial chiller and cooling system optimization
opportunities, two special 36-page supplements will be mailed out this year along
with the regular issue of Compressed Air Best Practices® Magazine.
N E W I N 2 0 15 !
Subscribe at airbestpractices.comand at coolingbestpractices.com
TWO SPECIAL SUPPLEMENTS FOR 2015!blower and vacuum system optimization
optimization
opportunities, two special 36-page supplements will be mailed out this year along
airbestpracticesairbestpractices.comcoolingbestpractices.com
cpCooling towers dissipate both ambient and process heat in most
large manufacturing facilities. These structures facilitate the transfer of
unwanted energy (heat) from a transport liquid (usually water) to the
atmosphere. Problems with efficient heat transfer, equipment protection
and pathological risks to employees can most often be traced back to an
issue with suspended solids. These solids can originate in the process,
in the piping, from the atmosphere or from internal biological growth.
Side-stream filtration is the most commonly used method of maintaining
minimal suspended solids in a cooling system. Side-stream filtration
takes a portion of the flow from the system and filters it to remove
suspended solids. It then returns the clean water back to the system,
usually through the cooling tower reservoir or sump. This method
maintains general control of suspended solids. It does not filter all the
water going to the process.
Historically, cooling systems have relied heavily on the two following
established methods for removing suspended solids. Cyclonic devices
are highly efficient at removing high specific gravity inorganic solids,
while granular media filtration is generally more effective at removing
low specific gravity organic solids.
Automatic self-cleaning screen filter technology provides a positive
barrier to both organic and inorganic solids regardless of specific
gravity and requires very little energy to operate. In addition, they
conserve coolant additives by using very little coolant liquid for the
self-cleaning process. The unwanted loss of coolant can be completely
eliminated by incorporating the cleaning cycle into the blow-down
process of the cooling system.
Applications
A large producer of cigarettes and fine-cut tobacco manufactures,
packages and ships billions of cigarettes per year. The plant installed
a new production line recently with all new equipment. One new piece
of equipment was a state-of-the-art, 150-ton magnetic chiller on the
evaporator loop of the cooling system.
Chillers are expensive components in a cooling system that must be
supplied with a continuous flow of clean water from a cooling tower.
Therefore, all the flow going to the chiller had to be filtered to protect
it from the possibility of damage induced by suspended solids. For this
application, a side-stream system was not appropriate.
Cyclonic separators could remove the heavier solids, such as sand
and pipe scale, but not the lighter organic and wind-blown materials.
Granular media filters could remove the organic fraction of suspended
solids, but would have trouble with sand particles since they would tend
Tobacco Producer Protects Chillers with
Self-Cleaning Filtration System
By Marcus N. Allhands, Ph.D., P.E., Orival, Inc.
TWO SPECIAL SUPPLEMENTS FOR 2015!In order to bring special attention to blower and vacuum system optimization
opportunities and industrial chiller and cooling system optimization
opportunities, two special 36-page supplements will be mailed out this year along
with the regular issue of Compressed Air Best Practices® Magazine.
N E W I N 2 0 15 !
Subscribe at airbestpractices.comand at coolingbestpractices.com
TWO SPECIAL SUPPLEMENTS FOR 2015!blower and vacuum system optimization
optimization
opportunities, two special 36-page supplements will be mailed out this year along
airbestpracticesairbestpractices.comcoolingbestpractices.com
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SUSTAINABLE MANUFACTURING FEATURES
to stay in the filter vessel during the cleaning cycle. Also, these filters
need to be taken offline during each cleaning cycle and require an
appreciable amount of water for cleaning.
Solution
An internationally known manufacturer of filtration equipment was
asked to recommend a filtration system to protect the chiller from
airborne debris scrubbed from the atmosphere by the cooling tower and
other solids originating within the cooling system. The solution had to
take into account that the system was likely to contain both organic and
inorganic solids, and that a continuous flow of water must be delivered
to the chiller at all times. Pressure losses had to be kept to a minimum
and flow rates could not vary appreciably.
A fully automatic self-cleaning filter with a 6-inch inlet and outlet flanges
and a 200-micron stainless steel screen element was recommended
for the application. The filter has a built-in bypass system that will
automatically open a bypass line around the filter element, should
anything cause the filter to fault. A filtration degree of 200-microns was
determined to be the most appropriate for this application to remove
particles capable of causing damage to the new chiller. This meant that
the openings in the screen were a little larger than the diameter of a
human hair and could remove airborne particulates, microbiological
growth, pollen and other materials found in most cooling towers. Figure
1 shows the final installation with the built-in bypass system.
Operation
The filtration unit consists of two stages of filtration. The components
of a typical filter of this type are depicted in Figure 2. The first is a
coarse cylindrical pre-filter (1) that removes rigid particles too large to
pass through the nozzles of the dirt collector during the cleaning cycle.
The second stage is a cylindrical stainless steel weave-wire fine screen
element (2) that is the real workhorse of the filter. The openings of this
element are of a specific size, representing the filtration degree of the
element (200 microns in this application).
Dirty water enters the inlet flange (3) and then passes through the
coarse screen described above, from the outside in. It then passes into
the center of the fine screen element. Water passes through this fine
screen from the inside out and exits through the outlet flange (4).
Unwanted solids accumulate on the inner surface of the fine screen
element. As this debris layer builds, energy is dissipated, causing a
pressure differential across the screen. When the control system senses
this differential pressure reaching a pre-set threshold (7 psi or 0.5
bar in this case), the cleaning cycle is initiated. The first step in the
cleaning cycle involves the automatic opening of the rinse valves (5)
to atmosphere. A pipe carries this flush water to a drain, but oversized
piping is used to prevent backpressure against these rinse valves. When
these valves open, the pressure in the hydraulic motor chamber (6) and
the dirt collector (7) drops abruptly.
The pressure just inside the nozzle openings on the dirt collector is
nearly zero gauge pressure, since these nozzles are connected through
the dirt collector, hydraulic motor chamber and rinse valves to the
atmosphere outside the pressurized filter body. Water inside the filter
Figure 2: Filter Components
TOBACCO PRODUCER PROTECTS CHILLERS WITH SELF-CLEANING FILTRATION SYSTEM
Figure 1: Filter Installation
Automatic Bypass Valve
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SUSTAINABLE MANUFACTURING FEATURES
rushes into the nozzles at very high velocity. It then passes through the
dirt collector into the hydraulic motor chamber and out the rinse valves.
The nozzle openings on the dirt collector are within a few millimeters
of the fine screen surface, causing water to pass backward through the
screen in a very small area at very high velocity. This dislodges the filter
cake (debris built up on the inside screen surface) and sucks it into the
dirt collector.
Since only a very small area of the screen is being cleaned by each
nozzle (an area about the size of a dime), there is plenty of energy
available for vacuuming debris from the screen. This debris is
discharged along with a small amount of water through the rinse valves
to the drain. As water rushes out of the dirt collector into the hydraulic
motor chamber, it passes through the hydraulic motor (8), imparting
a rotation to the dirt collector and thus moving the cleaning nozzles
around the inside surface of the screen. A hydraulic piston (9) then
slowly moves the dirt collector linearly, giving the rotating nozzles a
spiral movement. It moves in such a way that every square inch of
screen surface is passed by a suction nozzle, assuring that the entire
filter cake is vacuumed from the screen during the cleaning cycle. This
entire process takes less than 10 seconds and does not interrupt the
flow of clean water downstream.
Summary
Fully automatic self-cleaning screen filters provide an economical means
of removing suspended solids from cooling tower water. The use of
weave-wire screens as the filtering media provides a positive removal
system that eliminates all particles larger than the filtration degree of the
screen from the cooling system. It also removes many smaller particles
due to the filtration effect of the filter cake that builds on the screen
element surface between cleaning cycles.
This phenomenon of filtration improvement can be loosely quantified
as removing particles down to about one tenth the size of the screen
filtration degree when the filter cake is at its thickest. This 1:10
relationship is called the capture ratio as employed in screen filtration
systems. The efficient suction cleaning principle allows the filter cake to
be removed completely from the screen surface within seconds without
physically touching the cake or screen. During the suction cleaning
cycle, the filtration process is uninterrupted, which provides filtered
water downstream of the filter at all times and eliminates the need for
redundant equipment.
Water and chemical losses are kept to a minimum, and organic and
inorganic solids are removed with equal efficiency. Since only a small
pressure differential occurs across the screen element, the extrusion of
soft organic material through the screen is prevented. If any problem
should occur with the filter, the controller will sense this and open the
built-in bypass valve to provide a continuous flow of water to the new
chiller. The controller will then send a signal to notify personnel of the
problem for resolution.
Routine maintenance is minimal, and it consists of a monthly inspection
of the rinse valves to see that they are seating properly and an annual
inspection of the screen and hydraulic piston. An occasional manually
induced cleaning cycle by maintenance personnel is recommended to
assure proper operation. Full stream protection, automatic self-cleaning
process, automated bypass system and low maintenance were just the
qualities the engineers were looking for in a protection system for the
new magnetic chiller.
For more information, please contact Marcus N. Allhands, Ph.D., P.E., Vice President of Business Development, Orival, Inc. 213 S. Van Brunt Street Englewood, NJ 07631 Tel: (201) 568-3311 Email: [email protected] www.orival.com
“Full stream protection, automatic self-cleaning process, automated bypass system and low maintenance were just the qualities the engineers
were looking for in a protection system for the new magnetic chiller.”— Marcus N. Allhands, Ph.D., P.E., Orival, Inc.
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SUSTAINABLE MANUFACTURING FEATURES
cpNo matter what your application, there is a single formula for
determining the size of chiller you need. Before you begin, you must
know three variables:
1. The incoming water temperature
2. The chilled water temperature required
3. The flow rate
For our example, we will calculate what size chiller is required to cool
40 GPM (gallons per minute) from 70 °F to 58 °F? Use the following
five steps and general sizing formula:
1. Calculate Temperature Differential (ΔT ˚F)
ΔT ˚F = Incoming Water Temperature (˚F) — Required Chilled Water Temperature.
p` Example: ΔT ˚F = 70 ˚F - 58 ˚F = 12 ˚F
2. Calculate BTU/hr.
BTU/hr. = Gallons per hr x 8.33 x ΔT ˚F
p` Example: 40 gpm x 60 x 8.33 x 12 ˚F = 239,904 BTU/hr.
3. Calculate tons of cooling capacity
Tons = BTU/hr. ÷ 12,000
p` Example: Ton capacity = 239,904 BTU/hr. ÷ 12,000 = 19.992 tons
4. Oversize the chiller by 20%
Ideal Size in Tons = Tons x 1.2
p` Example: 19.992 x 1.2 = 23.9904
5. You have the ideal size for your needs
p` Example: a 23.9904 (or 25-Ton) chiller is required
Plastic Process Cooling Applications
There also industry-specific, rules-of-thumb for chiller sizing. These may
vary depending upon the application. The below guidelines and formula
may be used for sizing chillers for plastic process cooling applications.
In our example, we will calculate what size chiller is needed for a
A 20 ton cooling-capacity chiller from Cold Shot Coolers®
5 SIZING STEPS FOR CHILLERS IN PLASTIC PROCESS COOLINGBy Bob Casto, Cold Shot Chillers®
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SUSTAINABLE MANUFACTURING FEATURES
polypropylene molding operation that incorporates a 6 oz. "Shot Size"
and a 18 second cycle time with a 3 H.P. hydraulic motor. We will use
Charts 1 and 2 as references.
1. Calculate the pounds of material per hour being processed.
p` Example: 6 oz / 18 sec = 19.99 oz/min (20.00 oz/min)
p` 20 oz / min x 60 min. = 1200 oz/hr
p` 1200/16 = 75 lbs / hr
2. Determine how many pounds per hour are required for each ton of cooling capacity using Chart 1.
p` Example: Polypropylene requires 1 ton of cooling capacity for every 35 lbs/hr processed
p` 75 lbs. ÷ 35 lbs = 2.14 tons of cooling
3. Determine if the extruder or any auxiliary equipment will require chilled water using Chart 2. If not, go to step #5.
p` Example: A hydraulic motor requires 0.1 ton/HP of cooling capacity
p` 3 HP x 0.1 ton/HP = 0.3 ton of capacity
4. Combine the process and auxiliary equipment cooling requirements.
p` Example: 2.14 tons + 0.3 ton = 2.44 tons
5. Size your chiller by rounding up to the closest standard unit.
p` Example: This application will require a 3-ton unit
About Cold Shot Chillers®
Based in Houston, Texas, Cold Shot Chillers® manufactures
economical, ruggedly dependable industrial air cooled chillers, water
cooled chillers, portable chillers and central chillers. Our industrial
water-cooled chillers and air-cooled chillers serve a variety of different
industries and applications.
Cold Shot Chillers® began in the late 1970s as an HVAC repair company
in Houston, Texas. In 1980, the company began manufacturing new
chillers for the plastic process industry and refurbishing used chillers
for an assortment of industries. As our new chiller sales grew the
company emphasis shifted from service to 100% manufacturing.
Primary industries served include plastic processing, food & beverage,
and metal finishing.
For more information contact Bob Casto, Business Development Manager, Cold Shot Chillers®, cell: 281-507-7449, office: 281-227-8400, email: [email protected], www.waterchillers.com
CHART 2: AUXILIARY EQUIPMENT AND EXTRUDER COOLING REQUIREMENTS
EXTRUDER COOLING
Gear box cooling 1 ton/100 hp
Feed throat: 3” screw or less 1 ton
Feed throat: larger than 3” screw 2 ton
Barrel or screw cooling (per inch of screw diameter) 1 ton/inch
AUXILIARY EQUIPMENT COOLING
Air compressor (no aftercooler) 0.16 ton/hp
Air compressor (with aftercooler) 0.2 ton/hp
Vacuum pump 0.1 ton/hp
Hydraulic cooling 0.1 ton/hp
Hot runner mold 0.1 ton/hp
Water pump in circuit 0.1 ton/hp
Feed throat: less than 400 ton 0.5 ton
Feed throat: greater than 400 ton 1 ton
Source: www.waterchillers.com
CHART 1: PLASTIC MATERIAL PROCESS COOLING REQUIREMENTS
INJECTION MOLDING
30#/hr H.D. Polyethylene 1 ton
35#/hr L.D. Polyethylene/Polypropylene 1 ton
40#/hr Nylon 1 ton
50#/hr Polystyrene or ABS 1 ton
65#/hr PVC or Polycarbonate 1 ton
70#/hr P.E.T 1 ton
EXTRUSION
50#/hr Polyethylene/Polypropylene 1 ton
75#/hr Polystyrene 1 ton
80#/hr PVC 1 ton
BLOW MOLDING
35#/hr Polyolefins 1 ton
Source: www.waterchillers.com
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cpAir compressors are very effective heaters.
Over eighty percent of the energy input from
the motor is converted into compression
heat. That heat must be rejected from the
compressor package in a way that maintains
a variety of temperatures in a reliable manner.
The laws of physics demand that the air
temperatures go up with compression.
Since the most efficient compression is
“isothermal” (constant temperature), it is
important to reduce temperature during
compression, either by heat being absorbed
into oil with oil-flooded compressors,
or by using multi-stage compression and
intercooling with oil-free compressors.
Maintaining temperature in the correct
range is the most important reliability
issue in compressors, ensuring that it is not
too high and not too low. It also indirectly
affects air quality, since high air temperature
overwhelms dryers with water vapor.
Compressed air cooling systems come in two
types: liquid-cooled and air-cooled. While
liquid cooling with clean, chilled water is the
most effective, many industrial plants don’t
have this capability, particularly in mining
and material processing. They typically resort
to either air-cooled or fluid-cooled using a
cooling tower, which is still essentially air-
cooled. With the heavy dust load, this makes
for a challenging application.
The goals of this article include describing a
large mining compressed air system case study,
and, from a cooling perspective, discussing
the limiting factors and performance issues
of each of the cooling subsystems. Additionally,
the article will provide recommended
improvements to the project that will make
the system much more reliable.
Mining Application System Description
Current Compressed Air System Design
pp Three oil-free, two-stage screw compressors, 600 hp, 2,400 acfm, water-cooled, with open drip-proof motors, 25-years-old
pp Three regenerative air dryers, heated type, 2,200 scfm (with and without blower)
pp Filtration and storage
pp Distribution
pp High-pressure boosters
Current Cooling System Design
pp Water/glycol solution is the primary compressor coolant.
pp Glycol is pumped in a closed-loop system to two parallel plate-and-frame intermediate heat exchangers. It is then pumped to the compressors (in parallel) and back to the pump inlet.
pp Glycol is cooled on the other side of the intermediate heat exchanger by water. The water is pumped through the heat exchangers, and then to an open cooling tower and back to the pump inlet (Refer to Figure 1 and Table 1).
COOLING TOWER SYSTEM AUDIT for a Tough Mining Compressed Air ApplicationBy Tim Dugan, P.E., President, Compression Engineering Corporation
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Audit Results
The audit identified the following issues as
the primary problems with the supply side
of the current system:
pp The compressor had high temperature shutdown issues during the summer.
pp Compressors could not run fully loaded for a long time, requiring all three to cycle (not efficient).
pp There was water and condensation in the compressed air lines.
pp There were reliability issues in the booster pumps, which served the SAG mill clutches.
The first two issues are directly related to the
cooling system.
Cooling System Components, Limits and Performance
The components of the compressed air
system that are dependent on the cooling
system include:
pp Air Compression Elements: The heat is generated in the first and second stages through heat-of-compression. Due to the lack of heat transfer out of the compression chamber and slippage between rotors, the temperature rise is too high for compression to occur in one stage. Thus, two stages are used.
p` Limitations: Maximum temperatures are about 428 ˚F at the second stage discharge and about 380 ˚F at the first stage discharge. These limits are based on thermal growth and reliability.
p` Performance: The case study compressors are 25-years-old, and have worn rotors with more leak-back than a new compressor. Thus, their
Figure 1: Existing System Diagram
Table 1: Current System Baseline Data
CURRENT SYSTEM SUMMARY
OPERATING COST
Electrical Energy Approximately $326,000 per year*
Maintenance Approximately $175,000 per year
Total $500,000 per year
*Assuming $0.04 per kWh
PERFORMANCE
Peak Flow (July 2011) 6,886 acfm
Average Flow (Jan. 2012) 4,225 acfm
Average Pressure 114 psig
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temperature rise per stage was higher than when new, making them more vulnerable to overheating.
pp Dryers: The dryers in the case study were regenerative heated compressed air type. They use adsorption to dry the air. In a mine with ambient temperatures below freezing, this is the necessary type of dryer for avoiding freeze-ups.
p` Limitations: Dryers are designed for 100 ˚F inlet at 100 psig (100 percent saturated air). If the dryers are marginally sized (as they are in this case), the air temperature should be lower than 100 ˚F to the dryer.
p` Performance: Two of the three case study dryers are not achieving dew point. This is partly due to compressed air being higher than 100 ˚F (even in January).
The components of the cooling system include:
pp Cooling Tower: Cooling towers are available in “open” or “closed” configurations. Open-type evaporative coolers are the simplest, merely pumping the cooled water to the top of a heat exchanger. The cooling from airflow blows counter to the coolant, falling with gravity to the sump. The cooled water is in direct contact with the ambient air. Closed-type evaporative coolers separate the cooled fluid (inside a heat exchanger) from the air and spray water on the outside of the heat exchanger. Open towers are the lowest energy cost cooler (per BTU), but they are more vulnerable to fouling
from dirty air. The dirt in the air is “scrubbed” and ends up in the sump. It is then pumped throughout the system (See Figure 2).
p` Limitations: The limits of a clean open tower are the “wet bulb” temperature (dew point) and the “approach temperature,” or designed-in differential between outlet temperature and wet bulb temperature. More area and air flow result in a lower approach temperature and higher cost. A new open tower is usually sized for with 15 ˚F of the wet bulb, or closer.
p` Performance: The cooling tower from the case study had an approach of 30 ˚F, delivering 61 ˚F water out on a January day in Utah. The dampers were wide open. This is indicative of fouled heat exchangers.
pp Intermediate Heat Exchangers: Plate-and-frame heat exchangers are used to isolate the dirty water from the cooling tower and the compressor coolers. It is a good selection from a maintenance perspective, as it can be taken
apart and cleaned. Heat exchanger capacity can be increased by merely adding new plates.
p` Limitations: The limit of this heat exchanger is also area, and the approach temperature is inverse to the area and cost. A new plate-and-frame heat exchanger can be designed economically for a 5 to 10°F approach.
p` Performance: The case study heat exchanger delivered 82 ˚F glycol with 61 ˚F water from the cooling tower. It was a 21 ˚F approach, which was over double what it should be. This is likely from internal fouling on the water side.
pp Compressor Intercooler: Custom tube-and-shell exchangers are used to cool the air after the first stage of compression to the level needed at the inter-stage (not too low to avoid condensation). The heat exchangers have removable tube bundles, and typically are water in the shell, air in the tubes and counter-flow.
p` Limitations: The limit of this heat exchanger is also area, and the approach temperature is inverse to the area and cost. A new intercooler can be designed economically for 15 ˚F approach.
p` Performance: The case study heat intercoolers delivered an average of 109 ˚F air out, with peak temperatures as high as 122 ˚F. The average approach temperature was 27 ˚F. That high of an approach is usually from fouling. The coolant is supposed to be clean and isolated from the outside air. However, it is possible that
Figure 2: Open Cooling Tower Heat Exchangers
COOLING TOWER SYSTEM AUDIT FOR A TOUGH MINING COMPRESSED AIR APPLICATION
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Table 2: Winter Temperature Measurements and Calculation
Table 3: Summer Temperature Calculations
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the air-side is fouled from dirty compressed air entering the compressor.
pp Compressor Aftercooler: These are the same type and design as the intercoolers, designed for 100- to 125-psig air and a lower approach temperature.
p` Performance: The case study heat intercoolers delivered an average of 104 ˚F air out. The average approach temperature was 22 ˚F, which is too high.
We found that the total “approach temperature” of the system, which is the difference between the primary coolant, ambient air dew point, and the final air temperature out of the compressor, is 73 ˚F.
From the measurements in this system, we projected what the system temperatures would be on a summer day. The compressors would shut down on high second stage outlet temperature (428 ˚F) and high second stage inlet temperature (158 ˚F). Dryers would not achieve their dew point. Oil temperatures
would be high as well (See Tables 2 and 3).
Cooling System Modification Recommendations
In the audit, we recommended the following
changes:
1. Lower maintenance compressors: Since the compressors were close to the end of their useful life, the mine
was interested in replacing them. Though they are highly reliable, two-stage, oil-free screw compressors have significantly higher long-term maintenance costs than oil-flooded rotary screw and centrifugal compressors. Additionally, in the dusty environment, the current units had unique problems. Because of the high noise level of the compressor, the mine required the sound enclosures to be closed all the time. Because of MSHA rules, the sound enclosures are a “confined space,” which limited access. The motors were “open drip-proof” (ODP) and not visually inspected. The motor rotors became encrusted with dirt and overheated repeatedly. An open-type compressor package was recommended. That all said, the current supplier has had this type of compressor in mining applications all over the world, and could support the project with differently designed oil-free screw compressors.
2. Dedicated, closed-loop fluid cooler without intermediate heat exchangers: This would eliminate dirty air being scrubbed into part of the coolant, and reduce frequent maintenance to merely the external side of the cooling tower heat exchanger. The approach temperature from wet bulb to compressor inlet could be reduced
from 51 ˚F to 15 ˚F, eliminating the overheating problems.
3. Comprehensive monitoring and control: There are transmitters in the system that we saw in the drawings, but they were not being trended in the plant data historian. Nor did the maintenance and engineering staff have access to graphical display of the compressed air system showing key performance indicators. We recommended a comprehensive monitoring and control system, integrating compressors, dryers and a cooling system.
4. Comprehensive Maintenance: One compressor OEM had a maintenance contract for the compressors only. For unknown reasons, they were not also responsible for the dryers and cooling system. As a result, the dryers and cooling systems were neglected. We recommended a comprehensive maintenance approach, either in-house or outsourced.
In conclusion, cooling systems for compressed air systems in mining environments need to have special attention given to minimize the possibility of cooler fouling. Otherwise, the system will become unreliable, vulnerable to shutdowns and provide poor-quality air.
For more information, contact Tim Dugan, P.E., President, Compression Engineering Corporation by phone (503) 520-0700, or visit www.comp-eng.com.
COOLING TOWER SYSTEM AUDIT FOR A TOUGH MINING COMPRESSED AIR APPLICATION
“Cooling systems for compressed air systems in mining environments need to have special attention given to minimize the possibility of cooler fouling.”
— Tim Dugan, P.E., President, Compression Engineering Corporations
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cpThe Big Picture
Heat recovery opportunities have resulted in the largest amount of
savings of our common projects our industrial energy management
teams have implemented. It is not the easiest type of project to
implement but the amount of savings and the reduction of emissions
makes this project very worthwhile.
The first question I ask in workshops is: What is the purpose of the
cooling tower located outside of your plant? The answer: To remove
waste heat. Second question: Does it make sense to use a system
to remove heat from your plant and then use expensive natural gas
to provide heat for makeup air?
Many times I usually get the response: The low grade heat from the
coolant loop is not sufficient to provide the heat we need for our
factory. My answer: Is the coolant loop temperature >10 degrees F
warmer than the outside winter air temperature? Then warming the
incoming air will reduce the heating load. Look at this table of weather
data from Ohio. There are 4,000 hours where the average temperature
is less than 37 degrees F!
Project Review
Let’s begin the review of this project. Symptoms which can help identify
the opportunities for this project include:
1. The facility has sources of waste heat such as cooling towers or furnace or equipment exhaust.
2. The facility has a large amount of air exchange such as exhaust hoods, filtration systems, ceiling or wall exhaust fans.
3. Winter heating is required such as natural gas forced air, steam, or hot water systems.
Cooling Tower Dry Cooler
USING 4 WASTE HEAT SOURCES FOR HVAC OPTIMIZATIONBy Thomas Mort, CEM, Mission Point Energy
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Heat Source #1: Air-cooled Air Compressors
One of the simplest projects to get waste heat is from an air cooled
compressor. This is a common project but I continue to find plants
where this source of free heat is not being utilized.
A key to the success of this project is to be sure to use outside makeup
air for the intake and discharge the warmed air into the ceiling area of
the facility, not directly blowing on an individual.
To calculate the value of this free heat use this simple formula:
Air Cooled Air
CompressorAverage kw/hr
hours/year requiring
winter hear mmbtus/kwh $/mmbturecoverable
heat$Savings per year
Compressor #1
100 4000 0.00341214 $10,000 90% $12,284
Heat Source #2: Coolant Loop of an Injection Molder
Another method to recover waste heat is from the coolant loop. By
intercepting the water at its warmest point before it arrives to the
cooling tower and passing it through a radiator the heat in the water can
be used to provide warmed make up air.
This photo shows the coolant water from an injection molding machine.
The thermal image shows the temperature of the water. As you can see
the temperature of the coolant water is significantly above the outside
air temperature in the winter.
Weather Charts
Air-cooled Air Compressor
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Heat Source #3: Various Heat Wasters
The next diagram and shows a typical installation drawing. As with the
air cooled compressor it is important that this system be set up to bring
in outside makeup air and then exhaust the air into the ceiling area of
the facility.
Here is a photo of what I call a “Heat Waster”. This is exactly the type
of unit that could have the discharge air ducted into the plant during
the winter for free heat.
Here is the formula that can help to determine the value of heat
available:
Heat Recovery
from Coolant Loop
Differential Temperature
hours/year requiring
winter hearGPM Flow
Conversion to mmbtus $/mmbtu
$Savings per year
Water to Air Heat
Exchanger10 4000 100 0.00501 $10.00 $20,021
Many plants have been able to reduce their winter heat loads using
this concept. Many, even in Michigan and Wisconsin have been able
to eliminate the need for natural gas heat during production hours.
I have found a company that supplies this type of heat recovery device
along with some electronic measurement equipment which provides
details of the amount of energy and savings that is being recovered from
the coolant water. (www.amsenergy.com) This 100 gpm radiator unit
with a metering system can cost around $25 to $30,000.
Heat Source #4: Free Cooling
Another area to find savings is called “free cooling”. The concept of “free
cooling” is that when the outside temperature is more than 10 degrees
below the required coolant temperature the electric chiller can be
bypassed and the cooling tower can be used to provide the cooling with
a much lower energy use. Many facilities, especially those with injection
molding processes use electric chillers to cool molds and hydraulics. A
common temperature for the cooling loop ranges from 55 to 75 degrees.
Refer to the chart above and you can see there were more than 3,000
hours with an average temperature of 32 degrees in Ohio.
Injection Mold Coolant Injection Mold Coolant
Water-to-Air Heat Exchanger Water-to-Air Heat Exchanger Photo
“Many plants have been able to reduce their winter heat loads using this concept. Many, even in Michigan and Wisconsin have been able to eliminate the need for natural gas heat during production hours.”
— Thomas Mort, CEM, Mission Point Energy
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Calculating the savings is based upon the following formula:
Free Cooling kw/hr
hours/year temperature is <
46 ˚F Electric $/kwh$Savings per year
Electric Chiller 150 3000 0.085 $38,250
Free Cooling projects can often be combined with heat recovery projects
and allow using much of the same equipment and getting two types
of savings, electric from shutting down an electric chiller, and gas from
reducing the load on the makeup air heating units.
Summary
Combining heat recovery projects together with HVAC projects
described in the earlier article makes a combination where you can
significantly reduce winter heat costs and have projects meeting our
target of 1 year or less.
For more information please contact Thomas Mort, CEM, Chief Operating Officer, Mission Point Energy, tel: 502-550-8817, email: [email protected], www.missionpointenergy.com
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USING 4 WASTE HEAT SOURCES FOR HVAC OPTIMIZATION
Free-cooling Plate-and-Frame Heat Exchanger
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